Vulcanizing stud for tube making



Oct. 6,1925.

M. A. MARQUETTE VULCANIZING STUD FOR TUBE MAKING Filed Nov 7, 1923 IN' NTOR.

ATTORX/D I dered sheet of uncured rubber is laid on the Patented Oct. 6, 1925.-

UNITED STATES PATENT orrlcl-z.

MELVON A. MARQUETTE, OF CHICOPEE FALLS, MASSACHUSETTS, ASSIGTNOR TO THE FISK RUBBER COMPANY, OF CHICOIPEE FALLS, MZASSACHUSETTS, A CORPORATION or massacnusn'rrs.

V'ULCANIZING STUD FOB TUBE MAKING.

Application filed November 7, 1923. Serial' No. 873,297.

T0 allwhom it may concern:

Be it known that I, MELVON A. MAR- QUETTE, ,a citizen of the United States of America, residing at Chicopee Falls, in the county of Hampden and State of Massachusetts, have invented certain new and useful Improvements in Vuleanizing Studsfor Tube Making, of which the following is a specification.

My invention relates to a vulcanizing stud for forming inner tubes for pneumatic tires, and is particularly concerned with theremoving of the entrapped air and gas formedby alaminated valve pad during the process of vulcanization of the inner tube and valve pad.

Usually 1n making inner tubes, a calentable and a mandrel placed thereon parallel with one side and rolled over the sheet so as to ply it up into a tube, and then vulcanizing the rubber while so wrapped upon the mandrel. In order. that the rubber tube may be reinforced at that ortion through which the valve islater to e positioned in the tube it is necessary to provide the tube with a valve pad comprising a number of plies of woven fabric and of uncured rubber of successively varied size, these plies bein superposed upon one another. This va ve pad becomes incorporated with the tube during vulcanization and becomes a part thereof. According1 to the usual method of construction I ave found many tubes spoiled during vulcanization upon the mandrel because ofblowing or blistering of the rubber tube near the edge of the valve pad. This condition is partly due to entrapped air or gases caught between .the several plies of stock forming the'valve ad and partly due to moisture in the fabric p ies of the pad. This moisture turns into vapor by the heat of vulcanization. While the rubber tube is in the process of vulcanization the entra ped air and vapor formed inthe fabri plies of the valve' pad are expanded by the heat and move to the edges of the pad laminations Y and frequently break through the rubber stock at one or more points thus causin the blistering and blowmgIhave referre to. According to my in- ,ventio'n this result is avoided.

By means of my invention I build inner tubes free of-blow holes or blisters, with the same ease as'tubes have been built accordmg to prior practice. The departure from the usual practice obviates a serious defect inherent in the former practice. My invention will be described with reference to the accompanying drawings; in which- Fig. 1 shows a sheet of vulcanizable rubber composition with a laminated reinforcing valve padin position to be rolled about a tube forming mandrel.

Fi 2 is across-section taken on line 22 of Fig. 1 showing a detail of a valve pad or, base with a building stud through the The valve pad 10 shown in Figs. 1 and 2 i has an opening 11 through it at approximately the center of the plies. The opening is'of sufiicient size and shape to permit the placing of the building stud '12 in it.

This opening and stud may vary in size and shape as the purpose of the invention is to provide a space 13 inside the stud of suflicient capacity to contain all previously described gases and vapors expanded during the vulcanizing of the rubber tube and valve pad. The opening in the valve pad is preferably cut therein after the plies of fabricand uncured rubber have been'superposed upon one another, as it gives an opening with the same diameter throughout the entire length of it. 1

The building stud 12 or nipple may be made of fiber or metal or other suitable material and the shape of it ma be varied. For instance, it may be made 1n the shape of a hollow. cylinder with one end closed having holes in the sides, but I prefer to use the ty e ofbuilding stud shown in Fig.

5 with a anged portion 15. The flange 15 allows the stud to enter the opening in the valve pad on so far, and also may be used in removing t e stud from the pad after the tube has beenvulcanized. The valve pad with the hollow building stud 12 is placed upon the sheet of rubber 17 near the edge 16 as shown in Figs. 1 and 2. The flange of the building stud faces away from the sheet as in. Figs. 1, 2, and 3. The mandrel is placed parallel with the edge of the sheet which has the valve pad on 1t,

pocket. The mounted combination is next vulcanized upon the mandrel and the valve pad becomes incorporated in the rubber. tube 19 during the vulcanization. The closed pocket will receive and hold the air, gas and vapor as the tube is being vulcanizedo ye meaaea When the tube is vulcanized it is peeled off the mandrel, the stud can be removed then or may be removed at any other time prior to punching the hole in the tube for the valve stem. The valve pad will then be on the outside, so as soon as the valve pad and stud peel away from the mandrel the gas and vapor in the hollow stud will escape into the atmosphere, through the open end of the stud.

Having thus described my invention, I claim:

A vulcanizing stud. for use in tube making having a hollow body portion closed at one end and holes through the sides of the body portion.

MELVON A. MARQUETTE. 

